The present invention relates to a mechanical system for speed adjustment, particularly to one for adjusting drive speed for a motor.
Prior art devices, such as that described in U.S. Pat. No. 2,691.896, are said to provide variable speed power transmission but such devices necessarily comprise a complicated system containing a large number of moving parts, which leads to increased cost of manufacture and a greater likelihood for mechanical malfunction.
Other such devices, particularly those used more commonly with commercial sewing machines, in order to achieve variation of the output speed (i.e., the variation of the drive speed) to, e.g., a feeding mechanism for moving a workpiece past the sewing needle, require that the device be partially disassembled, leading to increased time and expense for changing the output speed.
The present invention significantly alleviates, or even overcomes substantially, the above drawbacks by providing a greatly simplified mechanism whose output speed is readily and rapidly adjusted and that is considerably less expensive to produce than many variable speed transmission devices heretofore known to the art.